Process of smelting zinc ores.



J. M. HYDE. PROCESS OF SMELTING ZINC ORES. APPLICATION FILED I'EB.13, 71914.

1, 1 1 8,01 2; Patented Nov. 24, 1914.

2 SHEETS-SHEET 1.

J. M. HYDE.

PROCESS OF SMBLTING ZINC 0113s. APPLIOATION FILEDIEBJB, 1914.

1,118,012, Patented Nov. 24, 1914. v

2 SHEETSSHEBT 2.

H 1| ll l grweufoz 26W j 76% A WW UNITED STATES PATENT OFFICE.

JAMES M. HYDE, or BERKELEY, CALIFORNIA.

PROCESS 0E s'MEL'rms znvc ORES.

To all whom it mag concern:

Be it known that I, JAMES" M. HYDE, a citizen of the United States, residing at Berkeley, in the county of Alameda and State of California, have invented certain new and useful Improvements'in Processes of Smelting Zinc Ores, of whichthe following is a specification.

My invention relates to a method of smelting metal-bearing materials containing zinc or any other volatilizable metal or metallic compound, and especially that class of ores containing zinc and other metals such as lead, copper, gold, and silver; and has for its object to recover such other metals in a molten state While at the same time the zinc or other volatilizable metal or metallic com-- pound is vaporized, and recovered. This object I attain by smelting the charge over a bath of slag or matte and out of contact with the gases of combustion used for producing the smelting heat.

The smelting operation may be carried out in furnaces such asare shown in the accompanying drawings, in which- Figure 1 is a vertical, transverse section through one type of furnace; Fig. 2 is a partial longitudinal section; Fig. 3 is a transverse section through a modifiedform of furnace; and Fig. 4 is a vertical longitudinal section.

Referring to Fig. 1, A is the furnace wall inclosing the heating-chamber and the retort structure B, which may be made of any material resistant to heat and the corrosive action of slag or matte, such as clay, s1l1ca, magnesite or basic bricks, chromite or carborundum, or of bricks or blocks coated with chromite, carborundum or other suitable material. In its lower portion, the structure B is provided with open arches C which permit the fused material to pass out into and fill the lower portion of the furnace A,

which. is provided with tap-holes l), E, F, for slag, matte,,and base bullion, respectively.

The level of the matte or slag bath is mamtained above the tops of the arches, so that the products of combustion from the gas burners G and H or other heating means have no' access to the charge within the retort B. I is a flue leading to astack for carrying ofl the waste gases. The retort B has an upper portion K extending above the furnace and rovided .with a charginghopper L. M,l are pipes for leading ofi the zinc vapors and N, N are condensers there- Specification of Letters Patent.

for. 10 is an internal, longitudinally arranged arch providing a heating-chamber beneath the charge and above-the slag, and provided with a burner G for furnishing additional heat to thecharge through the arch and directly to the slag. This arclr performs the further function of acting as a support for the charge.

In the modified form of furnace shown in Fig. 2, a perforated or open-bottomed retort B extends transversely across the furnace chamber. The ore is delivered through the hopper P into a charging-tube L in which is mounted a screw-conveyer O for forcing the material into the retort B which, at its opposite end, is provided with a tube M for conveying zinc vapors to the condenser N. Instead of a single retort B, a series of retorts may be used, which are supported upon a suitable structure R, provided, as in Fig. 1, with open arches C, which permit the Patented Nov. 24, 1914.

Application filed February 13, 1914. Serial No. 818,576.

molten mass to flow into the lower .portion of the furnace proper A, which is provided githFslag, matte, and base bullion taps D,

The operation of the process as carried out in the form of furnace shown in Fig. 1, is as follows: The charge of ore, mixed with the proper fluxes and reducing-agents, either loose or briqueted, is fed through the hopper L into the stack portion K of the retort B. As it passes downwardly, it is heated by the flame outside the retort and by heat from the arch 10, and is finally reduced and fused, the fused mass filling the lower portion of the retort and furnace to a point above the tops of the arches C, this fused mass thus acting as a liquid seal and preventing direct access of the products of com bustion to the ore charge. The descending column of ore is .of such height and density that the volatilized zinc which has a free exhaust from the smelting chamber into the condenser or conduit to the oxidizing chamber and bag house, will follow that course and will not pass out upward through the descending charge and be lost ,nor w1ll atmosphericoxygen enter the smelting zone through the descending charge. As a result of this smelting operation, the zinc is reduced and volatilized and the other metallic contents of the charge are collected in the molten bath formed in the lower portion of the furnace. The lead will be reduced and, with some of the gold and silver, will form a layer of base bullion at the bottom. The

copper will form a layer of matte al, so coi1 taining some gold or silver, superincumbent on the lead; and resting .on the layer of matte, will be a layer of slag. If nepessary, granulated matte, sulfids, or cement'co pper may be added to -the ;charge.to assist in the formation of 'a-matte. Cement copper would also act as a reducing agent, breaking up any zinc sulfide left, in the charge.

llhe volatilized zinc is delivered through the pipes M to the'c'ondensers N,.in which it is condensed 'to molten spelter, and from which it may be removed; in any, suitable manner. Where metallic zinc is desiredpthe z1ncbear1ng ore,if a sulfid,=should'be roasted, or-if a carbonate, should be calcined, so

that, as far as possible, the zinc shall exist the chargeas an-oxid. When zincoxid is to 'be produced, air may be admitted to the vapors driven on? from thecharge. and

the thus-produced 'zinc oxid'carried to a" bag house or. otherwise collected, as by an electrostatic fume arrester. Il[f; desired or necessary, reducing-gases may be introduced into the zinc vapors as they pass "to the zinc condensers. The process is carried out.

inthe urnace shown in Fig. 2, in substantiallyt esame way. p 4

It will be noted .that in y process the charge is not directly'subjected to combustion ".gases and. the oxidation of the; zinc,

and thevolatilization' and oxidation of the lead, are therebyprevented, the lead. and zinc being separately collected, the zinc in theform of spelter'or oxid and the lead as base bullion." It will be noted further that heat is supplied to the charge to be melted indirectly through the walls of the retort while the surface of the molten material outside the retort is directly subjected to the action of the heat and flame in the combu'stion chamber. This molten material is its therefore directly heatedand serves to coninstead of being separately tapped from the furnace, the whole fused mass. may be passed into-a 'fore h'earth and slag, matte, and bullion there; separated'in the well-known way.

{In the process of the recovery of zinc from its 'oresby the use of the retort furnace which is now the standard method of zinc-recovery, the consumption. of. labor,

fuel, and, refractory materials is high, the

" capacity of the furnace is low, because the units used are necessarily small, and the furnace work is intermittent or cyclic, and it is necessary to treat, in an. independent operatiom'the residues left after the-zinc is. recovered, which are" many cases of value because oftheir content of lead, copp er, and the precious metals. A further disaolyantage exists in that certain types of ores and concentrates contain mineral materials which flux and destroy the clay retorts inwhich the ore-is treated.

My process herein disclosed produces great economy in all of the essential features of zinc-treatment. The amount of fuel which is required is less than that now consumed in regular practice, as the process is inmost cases continuous for a considerable period of time and there are not therefore those heat losses which are occasioned by shutting down and discharging and charging an ordinary retort furnace. Further, the waste heat from the smeltingoperation is used for the heating of the advancing charge approaching the smelting zone and maybe still further used after leaving the furnace for the production of steam for power use. As the furnace is not intermittently heated and cooled, the expansion and contraction of the retorts which takes'place in the ordinary zinc furnace, is avoided, and results in considerable economy of materials, as-the life of the retorts is greater. The -material of the charge which ordinarily forms a residue requiring further and independent treatment if it contains valuable metallic constituents, is, by my process, smeltedin a single operation and from it may he recovered its content of copper, lead, and the precious metals in concentrated -and commercially desirable form, as in mattes, and base bullions.

' It is to be understood that by the term zinc, as usedin the specification and claims, 'is included any other material or materials susceptible oftreatment by the described process; and that by the term ore, as used in the claims, is meant not only ore, but any metal-bearing material, such as slag, concentrates, etc. The slags or matte forming the molten bath in the furnace inay be either that produced by the smelting operation, orif such slag or matte is of insuficient amount, may be augmented byadditionsfof already formed slags or mattes, either in-solid or molten condition.

ll do not herein claim the novel furnace retort above. the molten bath, and keeping the bath. molten by heat directly applied to the surface thereof outside'said retort.

2.. The processof smeltingzinci'ferous ores, whichcensistsf inhe'ah'ng the'ore mixed with fluxand 'red-ueing agent-r in an externally heated retort to a temperature sufficient to reduce the metallic constituents, collecting the molten materials in a bath beneath the charge, removing the zinc vapors from the retort above the molten bath, keeping the bath molten by heat directly applied to the surface thereof outside said retort, and separately removing the base bullion, matte and slag.

3. The process of smelting zinciferous materials byheating such materials out of contact with products of combustion to a reducing temperature over a bath of matte or slag kept molten by heat directly applied to a portion thereof, and removing the zinc vapors from above the molten bath.

4. The process of smelting zinciferous ores which consists in heating the ore mixed with flux and reducing agent in an externally heated retort to a temperature suflicient to reduce the metallic constituents, collecting the molten materials in a bath beneath the charge, removing the zinc vapors from the retort above the molten bath, condensing the zinc vapors to spelter, and keeping the bath molten by heat directly applied to a portion of the surface thereof outside of said retort.

5. The continuous process of smelting zinciferous ores which consists in continuously feeding the ore mixed with proper flux and reducing agent into an externally heated retort and smelting the mixture therein out of contact with the products of the combustion of the fuel whereby it is heated, removing the volatilizedzinc, and removing from the smelting chamber during the smelting operation the remaining constituents of the charge in molten condition.

6. The continuous process of smelting zinciferous ores which consists 1Il c0nt11111- ously feeding the ore mixed with proper.

flux and reducing agent into an externally heated retort, smelting the mixture therein out of contact with the products of the combustion of the fuel whereby it is heated, continuously removing and condensing the volatilized zinc, and removing from the smelting retort during the smelting operation the remaining constituents of the smelting operation in the form of a molten bath by heat directly applied to the surface of the molten bath outside of the retort in which smelting takes place.

8. The continuous process of smelting zinciferous ores, which consists in feeding ore mixed with the proper flux and reducing agent into an externally heated retort and smelting the mixture therein out of contact with the products of combustion of the fuel whereby it is heated, and maintaining an adequate supply of ore and flux during the smelting, removing the volatilized zinc and removing from the smelting chamber during the smelting operation the remaining constituents of the charge in a molten condition.

In testimony whereof I aflix my signature in presence of two witnesses.

JAMES M. HYDE.

Witnesses:

'Jos. H. BLACKWOOD, J. HQ BRIOKENSTEIN. 

